This invention relates to the art of drain cleaning apparatus and, more particularly, to an improved feed control arrangement by which a flexible snake of such apparatus can be axially advanced and retracted relative thereto during a drain cleaning operation.
Drain cleaning apparatus of the character to which the present invention is directed is generally comprised of a motor driven snake or drain cleaning drum in which the snake or drain cleaning cable is wound about the axis of the drum and is rotatable therewith. The drum has an open front end through which a free or outer end of the snake extends for entrance into a drain to be cleaned, and a feed control device for the snake is generally supported on the frame of the apparatus forwardly of the open front end of the drum for receiving the snake. The snake, as is conventional, is an elongate flexible member made of tightly wound spring wire, and the free or outer end thereof is adapted to be displaced outwardly and inwardly relative to the drum through operation of the feed mechanism.
Often, as shown for example in U.S. Pat. Nos. 3,882,565 to Irwin, et al. and 5,031,263 to Babb, et al., the snake feeding mechanism is comprised of three drive rolls circumferentially spaced apart to provide an opening through which the snake extends and which rolls are adapted to engage the snake so as to cause the latter to move inwardly or outwardly of the snake drum in response to rotation of the drum and thus the snake. Generally, two of the rollers are radially adjustable relative to the snake axis so as to enable the feed mechanism to accommodate snakes having different diameters, and the third roller is generally spring biased so that the snake is firmly captured between the three rollers. The rollers are either skewed relative to the snake axis to achieve driving of the snake, as shown in the patent to Babb, et al., or are externally grooved to have a contour corresponding to that of the outer surface of the snake.
In the feed control arrangements heretofore available for use in connection with power driven drain cleaning apparatus, including those specifically referenced above, the snake feed control arrangements are structurally complex, difficult to access with respect to cleaning and/or performing maintenance and replacement operations with respect to parts thereof, and require time-consuming adjustments or disassembly operations in connection with the initial feeding of the enlarged auger contoured end of the snake or an auger or blade attachment thereon through the feed device. In this respect, for example, the feed rolls are enclosed in a housing and cannot be easily accessed for cleaning, maintenance or replacement without at least partial disassembly of the housing, or removal of the rolls, whereby access in any event requires considerable time and effort. In the arrangements in which the feed rolls are mounted in a housing for radial adjustment relative to an opening through the housing for the snake, the supporting structures are complex, adjustment is time consuming and displacement of the rolls radially outwardly of the opening to accommodate withdrawal or insertion of the tip end of a snake is also time consuming, especially if it is necessary to remove one of the feed rolls. Structural complexity not only adds to the manufacturing costs but also often makes the operation of the mechanism cumbersome. Further, the inability to obtain accurate adjustment of the rollers relative to the axis of the feed mechanism can result in an erratic action during use of the apparatus, and such action poses undesirable wear on the component parts of the snake feeding mechanism and causes instability with respect to the support of the apparatus during operation thereof. Still further, some of the previous feed arrangements, such as that shown in the patent to Irwin, et al., require the use of a reversible motor in order to achieve feed of the snake in opposite directions relative to the drum. While others of the previous feed mechanisms, such as that shown in U.S. Pat. No. 4,580,306 to Irwin, provide for reversing the skew of the drive rolls so as to enable both extension and retraction of the snake in response to rotation of the drum in the same direction, the arrangements for adjusting the skew of the drive rolls is structurally complex and, most often, requires manual displacement of the adjusting mechanism to release driving engagement of the rolls with the snake.
A snake feed control device in accordance with the present invention is of simple structure and comprised of a mini-mum number of parts which are structurally interrelated so as to provide a feeding device in which the foregoing and other problems and disadvantages encountered in connection with such devices heretofore available are minimized or overcome. More particularly in this respect, a snake feeding device in accordance with the present invention is comprised of a pair of support members having aligned openings therethrough for receiving a snake and which are axially spaced apart and interconnected with one another by a plurality of snake driving roll units circumferentially spaced apart about the axis of the openings. The snake driving roll units include roll members mounted on shafts having axially opposite ends which are pivotally interconnected with the support members such that the latter can be rotated in opposite directions relative to one another so as to displace the snake driving rolls between a neutral position in which the rolls do not drivingly engage the snake and an actuating position in which the rolls drivingly engage the snake for displacing the snake axially relative to the feeding device. In the neutral position, the roller shafts are parallel to the axis of the openings through the support members and the driving rolls are radially spaced from the axis of the openings through the support members so as to enable the enlarged auger contour or attachment on the free end of a snake to be readily movable through the device. In the actuating position the roller shafts and thus the rollers are skewed relative to the axis and the rollers are in inner positions to engage a snake therebetween, whereby rotation of the snake and engagement of the rolls therewith displaces the snake axially relative to the support members.
Preferably, the support members are rotatably displaceable in opposite directions from the neutral position, whereby the drive rolls can be skewed in opposite directions relative to the openings through the support members so as to enable displacement of the snake in axially opposite directions relative to the feeding device without reversing the direction of rotation of the snake. This advantageously enables both extending and retracting the snake relative to a storage drum without having to reverse the rotation of the latter to achieve retraction of the snake thereinto. It is also preferred to provide for the axially opposite ends of the driving roll shafts to be pivotally interconnected with the support members by ball and socket type joints therebetween, and to provide a biasing spring arrangement by which the support members and driving rolls are biased to the neutral position and returned thereto when released from an actuating position. These features advantageously enable minimzing the number of component parts and simplifying the structure of the feeding device while improving the ease and reliability of operation thereof and minimizing the time and effort required to perform maintenance on and/or replace parts of a device.
It is accordingly an outstanding object of the present invention to provide an improved feed control device for axially feeding a snake in power driven drain cleaning apparatus.
Another object is the provision of a snake feed control device of the foregoing character which comprises snake driving rolls mounted between axially spaced apart, relatively rotatable support components for displacement between neutral and actuating positions relative to a snake extending through the device in response to relative rotational displacement of the support components.
A further object is the provision of a feed control device of the foregoing character wherein an enlarged auger shaped or other tip end of a snake can be moved through the device with the driving rolls in the neutral positions thereof without disassembly of any part of the device.
Yet a further object is the provision of a feed control device of the foregoing character in which the component parts can be readily disassembled to facilitate maintenance and/or replacement of parts.
Another object is the provision of a feed control device of the foregoing character which is easy to operate and reliable in operation and which is comprised of a minimum number of parts structured and structurally interrelated to provide a compact feed control device which can accommodate different sized snakes without structural modification or adjustment, which minimizes the time required to feed or retract a snake therethrough and which is more economical to produce and maintain than such devices heretofore available.